1. Field of the Invention
The present invention relates to a process-model generation method, a computer program product for generating a process model, and a pattern correction method, and, more particularly to a process-model generation method, a computer program product for generating a process model, and a pattern correction method, to be used for correcting optical proximity effects of a mask pattern.
2. Description of the Related Art
Generally, when a device pattern or the like is formed on a semiconductor device, a photolithographic technique is used to form a mask pattern on a film to be processed. Recently, however, as the mask pattern becomes finer, changes in pattern shape due to optical proximity effects at the time of photolithography are more noticeable. Therefore, when the mask pattern is formed, mask pattern correction taking into consideration changes in the mask pattern due to the optical proximity effects at the time of exposure, a so-called optical proximity correction (OPC) is performed.
For the correction of the mask pattern, a model based OPC has been known, in which after a test pattern is formed on the film to be processed by using the photolithography or the like, a photolithographic process model is formed based on actual measurement of, for example, a pattern width or the like of the test pattern, and an influence of the optical proximity effects is simulated by using the process model, to determine a position, a dimension, and the like of the mask pattern to be corrected (for example, see Japanese Patent Application Laid-open No. 2004-246223 (FIG. 7)).
However, in the model based OPC using only a specific process model, sufficient correction accuracy may not be ensured with respect to individual pieces of a mask pattern with a specific different width, space, or the like.